Furnace for the heat treatment of pulverulent, granular, or pulpy material



June 28, 1927.

L. HONIGMANN ET AL FUNACE FOR THE HEAT TREATMENT F PULVERULENTMGRANULAR, 0R PULPY MATERIAL Filed 06h16. 1925.

Patented June 2s, 1927.

UNITED STATESA `IamwIG EoNIGuANN, or BAD ToEz. ANn Enmnmcn GERMANY. Y

PATENT OFFICE?.

aAaTLrNG, or

` IUBNACE ron. TBE HEAT TREATMENT or rrrzuvElaULEN'r, GEANULAE., o3 rum?! MATERIAL.

Appuomnn mea nemer 1e, 11ans, serial No. cassa, and 1n Germany october e, 1aed.

Thejinvention relates to a furnace for the heat treatment of pulverulent, granular or pulpy material, for example, fr the drying, -low-temperature d1st1llat1on and gasl- 5- fication of peat, lignite or the hke. In particular it relates to a furnace of such type with an annular furnace chamber, a rotary hearth insidev they same for. contlnuously transporting the material o f the charge Y from a charging point to a discharging point, and means for supporting and transmitting motionto said hearth.

The purpose of the inventlon 1s to providesuch a furnace vin which the material can be subjected to effective heat treatment in a simple and inexpensive manner at small expense and in a short time. In particular it is intended to enable the charge materlal to be spread on the hearth, at the chargmg 9 point, in a very thin and very `un1form a layer, and to remove it from the furnace 1n a simple manner at the point of dlscharge.

According to the invention, a furnace of the type in question is characterizedin that the upper side of the rotary hearth is provided with projections, ledges or ribs, with grooves, channels or recesses, for the accommodation `of the char e material, hollowed.

outbetween them. is assures a particu- V -larly favorable distribution of the material on the surface -of the hearth, the heating surface of the bed of the hearth is considerably increased, and the transmission of heat to the chargejis improved. In order to en- 85 able the material to be distributed ina perfectly uniform thinlayer, the lower edge j s of the charging hopper at the charging point is arrange according to the invent1on, so

as to come into sliding contactl with the pro- 40 jections, ledges or ribs of the rotary. hearth,

so as to :sweep off the surplusanaterial in the grooves, channels `or hollows of the rotary hea h.

this arrangement, the material is car- 45. ri'd through the furnace chamber, from the charging polntto the,discharging point, in`

the recesses in the hearth plate, and is thusdried to a loose powder. This -material cannot be removed at the point of discharge by ordinaryl Scrapers, and therefore, according to the invention, means are provided for drawin the treated materiaLout of the recesses 1n the rotary hearth bythe suction effect ofa current of gas. This can be effected by drawing 0E the furnace conjointly with the treated material at the point -of discharge, passing the gas and.

material through a separator and then returning the gas to the furnace. This method prevents any admission into the furnace of fresh air, the oxygen of which might, for example, setup combustion in the material of the charge when fuels are being treated. In this manner, 'the major portion of the treated material is continuously removed.

An embodiment of the subject of the invention isv illustrated in the drawing.

Fig. 1 represents an embodiment of the new furnace in plan,

Fig. 2 a section alon the line II-H of 1 of one part of te annular furnace, an Y 11im of Fig., 1. l

Fig. 4 isla similar section along the line IV-Iv of Fig. 1.

In the embodimentshown, a furnace ac-`V Fig. 3 a similar section along the line` hearth c, consisting, for example, of a metal ,i plate c and an underlying` body c of firebrick. The hearth plate c is. provided, over its entire surface, with ribs or projections d, between which corresponding recesses d are hollowed out. The furnace chamber b 1`s shutoff against the outer' air b`y sand gutters e and water seals or the like e. The rotary hearth' 'c is .carried ring a tro afd by asupporting which by trolleys f is supported. on ley track g on which it is rotated by rivmg gear g.

arranged a charging vplpe on which is elastlcallyv suspended a sharging hopper h'. The lower edge of the charging ho per is in sliding contact with projecting l'e ges la on the plate c. A cross beamy' prevents the chargmg hopper from being carried. away by the vrotary vhearth plate. `Between the t the charglng'point. (section line II) is ledges k an adjustable scraper may be arranged on the. lcharging hopper said scra r sweeping directly overA the ribs d of the hearth c and ,thereby removing an surplus of the material runnmg out of the opper.

. At the .point of discharge l(section line 111) is arranged a second hopper Z', which 1s suspended from a suction ipe l. This pipe Z leads to the intake of a lower m, the

delivery side of which is connected to a dust "the charging opper h on to the surface of the hearth plate c. -This plate moves in la circular manner in the direction of the arrows m, .and in the course of this movement the chargin hopper k sweeps against the `ledge shape ribs k of the hearth plate. The

damp charge material falls into the recesses d of the hearth plate and is carried round by the rotary movement of same. 1n this movement the scraper i sweeps off the surplus material so asto leave a thin and very uniform layer. On the way from the charging/point 11 as far as the point of discharge 11 the material traverses the furnace chamber 1V and is thereby dried, reaching the point of discharge 11as a dry owder. At this .point the blower m, acting y way of the pipe l draws the furnace gas over the rotary hearth, and carries away the pulverulent product along with the gas. The mixture of gas and char e material reaches the separator n, where t e pulverulent product is separated, the dust-free gas being returned to the furnace by way of the pipe o.

As shown in. Fig. 4, the annular chamber b is surrounded by the heat passages y, e, through which pass the heating gases from a suitable furnace and which, by lindirect heating, accomplish the drying or distillation of the material upon the hearth c. This is a well known type of heating apparatus, and forms no part of the present invention.

1tv will be understood that the general arrangement of the heating chambers for the hearth are by way of example only and are already known in the art. The present invention relates to the provision of the annular ribs upon-the top of the hearth, to the means of forming a thin layer of charging material upon the hearth, and to the means for withdrawing the dried material without incurring the introduction of gases in the exterior. Suitable devices, already well known in the art, may be providedto regulate the discharge of furnace and other gases from the hearth chamber itself, such as a draw-oft' pipe fw which may be controlled by a damper having an external handle w.

Claims:

1. A furnace for the heat treatment of pulverulent, granular or pulpy material comprisingan annular furnace chamber, a

rotatable hearth in said chamber to continu ously transport the charging material from a'charging point to a discharging point, and

means for supporting and rotating said hearth, said hearth having annular projections on its upper surface to form grooves within which the charging material is placed, and means to remove the dried' material from' said grooves individually.

2. A furnace for the heat treatment of pulverulent, granular or pulpy material comprising an) annularfurnace chamber,` a rotatable hearth in said chamber to continuously transport the charging material from a charging point to a discharging point, means for supporting and lrotating said hearth, said hearth having projections on its upper surface to form grooves within which the charging material is placed, and a charging hop er to place the charging material u on said) hearth, said hop er presenting its ower edge into contact w1th the ro- ]'ections to remove the charging materia in excess of that for filling said grooves 3. A furnace for the heat treatment of pulverulent, granular or pulpy material comprising an annular furnace chamber, an imperforate hearth rotatable about 'a substantially vertical axis in said chamber to.

cintnuously transport the chang-ingl material from a charging point to a isc arging point, means for supporting and rotatin said hearth, means for charging the top o said hearth at the'chargin point with the charging material, 'a con uit terminating adjacent said hearth at the discharging (point in a hopper extending substantially ra ially for the width .of the layer of charging ma-l terial and with its opening located immediately above the material, and means to create a suction effect in sa'id conduit thereby remove said material from said hearth, and means to remove the material from said conduit. l

4. A lfurnace for the heat treatment of pulverulent, granular or pulpy materlal comprising an annular furnace chamber, a

rotatable hearth in said chamber to continuously transport the charging material from a charging. point to a discharging point, means for supportin and rotating said hearth,'means for de vering the charging material to the hearth at the charging point, a conduit terminating adjacent said hearth at the dischar g point in a ho per extending substantia ly radially for t e width pf the layer of charging material and with its opening located immediately above the material, a separator, said furnace chamber and hearth being shut off from the atmosphere, means to draw off the furnace gas and the treated material through said conduit from the discharging point and into. said separator, and means to return the gas to the furnace.

5. A furnace for the heat treatment of pulverulent, granular or pulpy material comprising an annular furnace chamber, a

rotatable hearth in said chamber to continuousl transport the charging material from a c arging point to a discharging point, means for supporting and rotating said hearth, said hearth having projections on its upper surface to form grooves within which the charging material is` placed and a ateral ledge at the edge thereof, and a char ingl hopper to place the charging mai teria upon the said hearth, said hopper presenting its lower edge into contact with said ledge whereby to act as a scraper to remove the excess of the charging material and to provide a thin uniform layer upon said hearth.

In testimony whereof We have signed our names to this specification.

LUDWIG HONIGMANN. FRIEDRICH BARTLING. 

